On November 12, 2009, Google announced that it had acquired Gizmo5[1] for a reported $30 million in cash. Prior to this acquisition, Gizmo5 had a working relationship with GrandCentral (now Google Voice) for years.[citation needed] Upon announcement, Gizmo5 suspended new signups until a Google relaunch.[5] Google was also dogfooding a Google Voice desktop client based on Gizmo5, branded as Gizmo5 by Google.[6]

On April 3, 2011 Google shut down Gizmo5 and recommended users to use Google Talk instead.[7]

The Gizmo5 mobile phone application used the phone's carrier voice network for all calls. The service called the phone numbers of both parties and bridged the call. On mobile phones that support SIP applications, calls may be placed over WiFi or 3G. In the case of WiFi, calls to Gizmo5 users were free, and calls to the public switched telephone network were charged Gizmo5 Call Out credit. On 3G, additional costs would apply depending on the user's data plan.[citation needed]

On August 26, 2010 Gmail accounts with Google voice were given a function to make and receive calls. Google Voice product manager, Vincent Paquet, confirmed that this function was added through the help of the technology received after the Gizmo5 acquisition.[13]

On Fri, Mar 4, 2011, subscribers received the following message from Gizmo5, indicating that the service would be terminated.

"Gizmo5 is writing to let you know that we will no longer be providing service starting on April 3, 2011. A week from today, March 11, 2011, you will no longer be able to add credit to your account.

Although the standalone Gizmo5 client will no longer be available, we have since launched the ability to call phones from within Gmail at even more affordable rates.

If you purchased calling credit and have a balance remaining in your account, you can request a refund by logging in to http://my.gizmo5.com. If you are in the United States, you can instead choose to transfer your credit to a Google Voice account, so it can be used for calling from Google Voice or Gmail. If you don’t have a Google Voice account, please create one so that we can transfer your credit.

Please request a call credit transfer or refund by April 3, 2011. If you don't request a call credit transfer or refund by this date, we will automatically refund your remaining call credit via the payment method you originally used to purchase the credit...."[citation needed]

There was no indication made if the service would be revived in another form, or if there would be similar functionality added to any of Google's current telephony offerings. On April 4, around midnight for most users, service was finally cut.[vague]